The theme of this program in molecular toxicology is elucidation of the fundamental mechanisms of action of pesticides and other toxicants so that the applied aspects of environmental toxicology may be more logically approached. The program is divided among faculty members each of whom has responsibility for a discrete, but interwoven, part of the overall program project. The molecular aspects of the program include elucidation of enzymic actions in pathways of metabolism, alteration of metabolism by toxicants, characterization of enzymes directed to the specific mode of action of pesticides as well as the distribution and storage of toxicants by macromolecules and subcellular units. Environmental toxicology encompasses a direct examination of the action of toxicants on target and non-target oganisms as well as examination of subtle effects of toxicants in the environment, particularly their behavioral and genetic action and effects on reproductive performance. A small, but important, aspect of the program is directed toward current problems in environmental toxicology which are uniquely encompassed within the expertise of this group of investigators.